A variety of tools and services exist for enabling network users to view information or “metadata” regarding the web pages, web sites, and other network resources they access. For example, a variety of browser toolbars exist that retrieve and display information regarding the page or site currently being viewed. This information may include, for example, a traffic ranking of the site, a categorization of the site, and a list of related sites or pages. Tools also exists for enabling a user to, prior to following a link, view a preview (such as a thumbnail image) of the page to which the link points. The preview is typically displayed when the user hovers a mouse pointer over the link.
Although these tools are sometimes helpful, they frequently do not provide users with sufficiently useful information for making informed decisions about whether to access particular pages or other network resources. In addition, many existing tools require the user to download and install a special browser plug-in, or only provide metadata for a very limited set of pages or sites.